[ntp:questions] Stability problem on PowerEdge (SuSE 9.3)
Richard B. gilbert
rgilbert88 at comcast.net
Sat Feb 24 17:43:24 UTC 2007
Till Wimmer wrote:
> Hi there,
>
> i try to settle some time accuracy in our office environment...
>
> Our main server is running SuSE 9.3 on AMD64. I installed the xntp
> package from SuSE (Vers. 4.2.0a-35).
> Hardware: DELL Power Edge 2850
>
> uanme -a:
> Linux office 2.6.11.4-21.15-smp #1 SMP Tue Nov 28 13:39:58 UTC 2006
> x86_64 x86_64 x86_64 GNU/Linux
>
> /etc/ntp.conf:
> --- snip ---
> driftfile /var/lib/ntp/drift/ntp.drift
>
> server 127.127.1.0
> fudge 127.127.1.0 stratum 13
>
> server 0.debian.pool.ntp.org iburst
> server 1.debian.pool.ntp.org iburst
> server 2.debian.pool.ntp.org iburst
> server 3.debian.pool.ntp.org iburst
>
> disable auth
> --- snap ---
>
> Short after starting, everythings looks ok:
> remote refid st t when poll reach delay offset
> jitter
> ==============================================================================
>
> *typhoon.aput.ne 192.12.19.20 2 u 227 256 377 170.905 -14.600
> 5.776
> +bitvalve.org 192.53.103.108 2 u 166 256 377 32.163 -15.190
> 4.488
> +8.15.10.42 132.163.4.103 2 u 170 256 377 105.118 -11.706
> 3.857
> -ns.oredin.net 193.190.230.66 2 u 179 256 277 141.835 36.960
> 17.438
> LOCAL(0) LOCAL(0) 13 l 49 64 377 0.000 0.000
> 0.001
>
> But after 3..5 hours all peers are rejected (ntpq> as) and LOCAL(0) is
> the sync source.
>
> I checked the firewall, disabled all restrict settings, disabled chroot
> and running as unprivileged user, a.s.o.
>
> Now i found that pps stability is always 512ppm and pll has a huge offset.
>
> ntpdc> kern:
> pll offset: 4294.95 s
> pll frequency: 22.694 ppm
> maximum error: 0.364061 s
> estimated error: 0.017754 s
> status: 0001 pll
> pll time constant: 4
> precision: 1e-06 s
> frequency tolerance: 512 ppm
> pps frequency: 0.000 ppm
> pps stability: 512.000 ppm
> pps jitter: 0.0002 s
> calibration interval: 4 s
> calibration cycles: 0
> jitter exceeded: 0
> stability exceeded: 0
> calibration errors: 0
>
> I set the hwclock -w and started fro scratch, but short after the offset
> was the same.
> I can't believe that the clock of this server is this terribly
> inaccurate... IMHO it's "professional" hardware. At least it was
> expensive ;)
>
> Any help would be very much appreciated!
> Till
>
Three of your servers have round trip delays that are extreme by most
standards. Try to find servers closer to you. I don't use pool servers
myself but I believe that you can select regional servers by; e.g.
us.pool.ntp.org for servers in the United states
eu.pool.ntp.org for servers in Europe
etc.
Twenty milliseconds round trip delay is a good number. Make every
effort to stay below thirty milliseconds.
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